Referring to FIG. 1, a vacuum system is generally equipped with an ejector 1 excavating an enclosed space using compressed air flowing therethrough at a high speed, a housing 2 defining the enclosed space, and an adsorption pad 3 communicating with the housing 2. When the compressed air flows through the ejector 1 at high speed, air in the pad 3 is drawn toward the enclosed space, which is in a vacuum state, and is discharged outside along with the compressed air. At this time, a vacuum is formed in the enclosed space, and negative pressure is created in the adsorption pad 3. A workpiece 4 can be transferred by this negative pressure. In this vacuum system, an air filter cartridge 5 is installed between the housing 2 and the adsorption pad 3, and prevents dust, foreign materials, etc. on the workpiece 4 from entering the ejector 1.
FIG. 2 illustrates a known filter cartridge 5 used in the vacuum system. The filter cartridge 5 includes an inlet 6 oriented to the adsorption pad 3, an outlet 7 oriented to the ejector 1, and a filter 8 disposed therein. The filter cartridge 5 is disposed on an intake line between the adsorption pad 3 and the ejector 1, and is designed so that foul air flowing in through the inlet 6 is filtered through the filter 8, and then flows out through the outlet 7 (see arrows). Of course, the filter cartridge 5 plays a useful role of filtering the foul air in the vacuum system.
However, since the filter cartridge 5 is additionally mounted on the intake line of the vacuum system, the use of the filter cartridge 5 does not meet the general demand for a more simple and compact vacuum system. Moreover, the intake line of the vacuum system is long, so that the vacuum response speed to the compressed air is decreased, and vacuum loss is increased.